From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sat, 25 Sep 2021 13:21:45 +0000 (+0100)
Subject: update table for scalar source
X-Git-Tag: DRAFT_SVP64_0_1~7
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=03a8959b3f7777304baa58d5f723cb02b54660f0;p=libreriscv.git

update table for scalar source
---

diff --git a/3d_gpu/architecture/dynamic_simd/assign.mdwn b/3d_gpu/architecture/dynamic_simd/assign.mdwn
index bec2ebdd9..df5b08c0c 100644
--- a/3d_gpu/architecture/dynamic_simd/assign.mdwn
+++ b/3d_gpu/architecture/dynamic_simd/assign.mdwn
@@ -44,6 +44,8 @@ smaller value (A) into the larger partition (B) then, depending
 on whether A is signed or unsigned, sign-extends or zero-extends
 *on a per-partition basis*.
 
+# Scalar source
+
 When the source A is scalar and is equal or larger than
 the destination it requires copying across multiple
 partitions:
@@ -59,5 +61,16 @@ The partition options are:
 | 000       | A7A6 | A5A4 | A3A2 | A1A0   |
 | 001       | A5A4 | A3A2 | A1A0 | A1A0   |
 | 010       | A3A2 | A1A0 | A3A2 | A1A0   |
+| 011       | A3A2 | A1A0 | A1A0 | A1A0   |
 | 100       | A1A0 | A5A4 | A3A2 | A1A0   |
+| 101       | A1A0 | A3A2 | A1A0 | A1A0   |
+| 110       | A1A0 | A1A0 | A3A2 | A1A0   |
 | 111       | A1A0 | A1A0 | A1A0 | A1A0   |
+
+When the partitions are all open (1x) only the bits that will fit across
+the whole of the target are copied.  In this example, B is 8 bits so only
+8 bits of A are copied.
+
+When the partitions are all closed (4x SIMD) each partition of B is
+2 bits wide, therefore only the *first two* bits of A are copied into
+*each* of the four 2-bit partitions in B.